Cloud computing is the use of computing resources (hardware and software) which are available in a remote location and accessible over a network, such as the Internet. Users are able to buy these computing resources (including storage and computing power) as a utility on demand. Cloud computing entrusts remote services with a user's data, software and computation. Use of virtual computing resources can provide a number of advantages including cost advantages and/or ability to adapt rapidly to changing computing resource needs.
A cloud computing installation may include hundreds or thousands of resources. During the lifecycle of each of these resources, the resources may fail or begin to perform poorly. Thus, it may be desirable to monitor the health and/or performance of the resources so that broken or poorly performing resources can be repaired and/or removed from service. One solution for monitoring the resources is to have a suite of diagnostic tests that periodically run on each resource. The results from the suite of diagnostic tests can be stored in a central location that can be queried for patterns and trends. Since running the suite of diagnostic tests consumes resources that can be used by customers, the diagnostic tests are typically designed to use a small amount of resources and are run infrequently.
Real-time results can be obtained when a system administrator executes ad hoc commands on suspect resources via parallel secure shell (SSH) sessions. This may be useful when attempting to identify new problems with the resources or when a more comprehensive and resource-intensive diagnostic test is desired. However, using ad hoc commands increases the risk of crashing the resource and the customer instances running on the resource. To reduce the risk of crashing the resources, a new diagnostic test typically undergoes a review process. However, it can take several weeks for the diagnostic to be reviewed, added to the existing suite of diagnostic tests, deployed on the resources, and have the results from the new diagnostic reviewed.